Apparatus for submarine signaling



Sept. 24, 1946.

E. E. TURNER, JR

APPARATUS FOR SUBMARINE SIGNALING Original Filed July 22, 1939 3 Sheets-Sheet 2 INVENTOR.

EDWIN E.TUI2NER JR.

ATTORNEY E. E. TURNER, JR APPARATUS FOR SUBMARINE SIGNALING Original Filed July 22, 1939 a Sheets-Sheet s ATZUENEY Patented Sept. 24, 1946 APPARATUS FOR SUBMARINE SIGNALING Edwin E. Turner, Jr., West Roxbury, Mass., as-

signor, by mesne assignments, to Submarine Signal Company, Boston, Mass., a corporation of Delaware Original application July 22, 1939, Serial No. 285,910. Divided and this application August 26, 1941, Serial No. 408,370

9 Claims.

The present application is a division of my copending application Serial No. 285,910, filed July 22, 1939.

The present invention relates to translating devices for converting compressional wave energy to electrical energy and vice versa. More particularly, the present invention relates to such devices as used for signaling under water and is particularly concerned with the transmission and reception of compressional wave energy in a beam.

It has heretofore generally been understood that if a vibratable piston be made large in its dimensions in comparison with the Wave length of the compressional waves at the signaling frequency, a concentration of energy along the axis perpendicular to the radiating surface will be obtained. However, such a concentration of energy in a main beam is accompanied by smaller 7 concentrations of energy indirections at various angles with the axis of the main beam.

When the relative acoustic energy intensities in space in the free medium as produced by such a device are plotted with respect to the several angular directions from the axis perpendicular to the radiating surface as on polar coordinate graph paper, the main concentration of energy will appear as a large lobe representing the main beam, and a plurality of auxiliary lobes or ears representing the subsidiary energy concentra-- tions in directions other than that of the main beam will also appear. These auxiliary lobes of the energy distribution pattern are often objectionable particularly for signaling under water as in acoustic ranging for the determination of the distance and direction of remote objects. Such subsidiary energy concentrations can be reduced by not driving the plane radiating surfaceas a piston but by driving it at varying amplitudes over its surface. A suitable amplitude distribution for this purpose will be shown below, but the present invention is primarily concerned with arrangements for obtaining any desired vibrational amplitude distribution of the radiating surface.

It should be noted that the characteristics referred to herein as applying to a compressional wave producing device also apply when the same device is used for receiving such waves.

In my copending application, above mentioned, I have described and claimed certain arrangements for producing desired variations of amplitude or response of a radiating and receiving surface, particularly by way of producing a flux 2 variation in a plurality of magnetic driving elements distributed over the radiating element.

The present application relates more particularly to the production of such variations in vibrational amplitude or response by constructions involving a variation in the mass ratios of a plurality of driving elements distributed over the radiating surface.

The invention will best be understood by the following description taken with reference to the accompanying drawings in which Fig. 1 is a polar diagram of representative compressional wave energy distribution; Fig. 2. is a graph showing'a suitable radiating surface amplitude distribution for the production of one of the energy distributions shown in, Fig. 1; Fig. 3 shows diagrammatically a vertical cross section of an electrodynamic oscillator in accordance with one modification of the present invention; Fig. 4 is a horizontal section of the same device taken along the line 44 in Fig. 3; Fig. 5 is a vertical cross section of another modification of such an electrodynamic oscillator; Fig. 6 is a verticalsection of a further modification of an electrodynamic oscillator; Fig. 7 is a horizontal section of the device of Fig. 6 taken along the line 'l-l; Fig. 8 is a vertical section of a still further modification of an electrodynamic oscillator; and Fig. 9 is a horizontal section of the device of Fig. 8 taken along the line 99.

As shown in Fig. 1, the energy distribution produced in a free medium by a representative extended, continuous, finite, plane radiating surface having a dimension greater than the wave .-.of energy concentration at various angular dis-. tances from the axis y as indicated in Fig. 1 by the lobes e1, c2 and es. If the piston be circular, it will be understood that these subsidiary lobes are in the form of hollow cones, the graph in Fig. 1 indicating merely the energy distribution in one plane.

A more desirable energy distribution pattern can be obained by effectively varying the ampli- I: u] tude over the radiating surface from the edges to the center so that the greatest amplitude will occur at the center. If, for example, the vibrational amplitude be varied as shown in Fig. 2, the energy distribution represented by the solid curve in Fig. 1 can be obtained.

In Fig. 2 the linear amplitude of the radiating surface is indicated by the ordinates which represent the ratio Ar/AO representing the ratio of the amplitude at any radial coordinate measured from the center of the radiating surface to the amplitude at the center, sothat the maximum amplitude is indicated as unity. Radial distances from the center of the radiating surface are indicated by the abscissae which specifically represent the ratio r/a where r is the radial distance from the center at any oint and a is the total radius of the radiating surface. The particular amplitude distribution curve shown in this figure follows the equation:

The amplitude distribution shown in Fig. 2 pro duces an energy distribution in the medium as shown by the solid curve in Fig. 1'. The main lobe E0 has somewhat greater width than the main lobe 60 produced by uniform amplitude of the vibrating surface but the auxiliary lobes E1, E2 and E3 are very much reduced in intensity;

To produce such a desired energy distribution or any other desired energydistribution it is necessary to cause the radiating surface to vibrate with varying amplitudesover its surface when energy is being transmitted and conversely to cause the surface to produce electrical response which varies in a similar manner when receiving.

According to the present invention I produce such a desired energy or sensitivity distribution by providing different loadings. of the driving elements, that is I vary the mass ratio between the mass of the driving elements and their respective associated proportionsof mass of the radiating element.

Figs. 3' and 4 show a suitable construction of a compressional wave transmitter and/or receiver in which the varying mass ratios between driving elements and radiating surface are obtained by varying the thickness of, the radiating member. An element 33' having a radiating surface in contact with the signaling medium has a plurality of concentric rings 5 of electrically conductive materi"al mcunted on its inner surface. Four such rings are shown in the drawings although more may be used if desired. A magnetic field is produced across each of the rings 5 by means of an electromagnet 6 having a 'plurality of concentric poles extending between the rings and excited by direct current polarizing coils 7; side surfaces of the concentric poles are alter-' nating current windings 8' to which energy is. suppliedat the signaling frequency. The rings 5 are proportioned to havea height such that together with their respective portions of the element 33', they will each form'a half wave length vibrating system at the signaling frequency. The entire system will, therefore, be set into vibration when the coils '8 are energized and conversely willgenerate an electromotive force in the coils B when the system is vibrated by compressional waves. An electrodynamic oscillator of this type is described in greater detail- Wound on or embedded'in the out- 4 in my copending application Serial No. 24,078, filed May 29, 1935.

The alternating current coils as well as the polarizing coils are connected electrically to have uniform excitation and to produce uniform electrical response when vibrated. However, contrary to prior usage, the inner surface 32 of the radiating element 33 is made dish-shaped. By this means the outermost ring is associated with a much larger mass than is the innermost ring. As before stated, all the rings, however, are tuned to the same. frequency and the length of the several rings consequently varies. Therefore, the mass ratio varies between the successive rings whereby uniform excitation of the driving coils will produce a varying amplitude distribution of the radiating surface. Thus any desired amplitude distribution can be obtained simply by making the surface 3.2 of a different shape to conform with the particular distribution desired. It will be evident to those skilled in the art that magnetostrictive driving elements may be used in place of the electrodynamic elements herein shown. The magnetostrictive elements may, for example, be in the form of a plurality of magnetostrictive tubes or rods as shown in my copending application Serial No. 285,910, filed July 22, 1939.

The mass. ratio between the various driving elements of the radiating surface can also be varied by the arrangement shown in Fig. 5. In this case the radiating element 34 has its inner surface divided by narrow circular slots intoa plurality of rings 36, 31, 38 and: 39, each drivenby one or more electrodynamic. elements 5 which may be the. same as those shown in Fig. 3 and in. horizontal section would appear as in. Fig. 4. The

outermost portion 36' of the radiating member is 1 shown.

A further arrangement for obtaining a desired amplitude distribution: over the radiating surface. by variation of the mass ratios, of. the several driving elements is shown in Figs. 6' and '7... In this ;case the electromagnetic drivin rings, of. which four are shown, number'ed55, 56, 5! and" 58, are

made of successively diminishing thickness,.the:

thickest ring, being placed near the center. As

in the other modifications. the ringsare all: tuned.

to the same frequency having regard to the; respective proportions of mass of the radiating element 59 which is associated with each. Each ring, therefore, together with its proportion of the element 59 forms a one-half wave length sys.-

tem at the signaling frequency. Since the ring at the center is thicker than the other rings, the ratio of its mass with respect to the portion of the mass of element 59 associated with it is larger than the corresponding mass ratio for the other rings. The central portion of the radiating element 59 will therefore be driven at a greateramplitude, and the amplitude will grad-- ually decrease toward the edges for successively decreasing ring thicknesses as shown- It willbe evident from what has been saidwithreference '5 to the other modifications that the variations in the thickness of the successive rings can be made to bring about any desired amplitude distribution over the radiating surface. It will also be evident that the same arrangement can be applied where magnetostrictive driving elements are employed. 1

In this case the tubes or rods near the center of the diaphragm will be made thickest and successively thinner elements will be used at points out from the center to conform to any desired radiating surface amplitude distribution.

A still further modification for obtaining varying mass ratios is shown in Figs. 8 and 9. In this modification the driving rings are again all of uniform thickness but are spaced different distances apart so that the several rings are associated with more or less of the mass and surface area of the radiating element, here numbered 60. Where a large amplitude at the center of the radiating surface is desired, the drivin elements are spaced most closely at the center as shown. Since all the driving elements are supplied with the same power, those at the center being required to move the least radiating surface area, will drive the latter with the greatest amplitude. In this manner any desired amplitude distribution can readily be obtained. Where magnetostrictive driving elements are employed, they, too, of course, will be spaced close together at those areas of the radiating member where the greatest amplitude is desired.

Having now described my invention, I claim:

1. A compressional wave signaling device having a transmitting and/or receiving member with a continuous finite transmitting and/or receiving surface adapted to contact the signalin medium, said surface having dimensions greater than the wave length of the compressional waves of the signaling frequency as measured in the signaling medium, and means for vibrating and/ or producing electrical response to vibration of said surface including a plurality of electroacoustic transducer elements mounted on and distributed over the opposite side of said member, each of said elements together with that portion of the mass of said member associated therewith form- 'ing a one-half wave length vibrating system at the signaling frequency, the mass ratios of the several transducer elements varying progressively over the area of said member in accordance with a predetermined law.

2. A compressional wave signaling device having a transmitting and/or receiving member with a continuous finite transmitting and/or receiving surface adapted to contact the signaling medium, said surface having dimensions greater than the wave length of the compressional wave of the signaling frequency as measured in the signaling medium, and means for vibrating and/or producing electrical response to vibration of said surface including a plurality of electroacoustic transducer elements mounted on and distributed over the opposite side of said member, each of said element together with that portion of the mass of said member associated therewith formin a one-half wave length vibrating system at the signaling frequency, the length and cross sectional areas of the several transducer elements varying progressively over the area of the receiving member to provide varying mass ratios.

3. A compressional wave signaling device having a transmitting and/or receiving member with a continuous finite transmitting and/or receiving surface adapted to contact the signaling medium, said surface having dimensions greater than the wave length of the compressional waves of the signaling frequency as measured in the signaling medium, and means for vibrating 'and/or producing electrical response to vibration of said surface including a plurality of electroacoustic transducer elements mounted on and distributed over the opposite side of said member, each of said elements together with that portion of the mass of said member associated therewith forming a one-half wave length vibrating system at the signaling frequency, the thickness of the portions of said member associated with the several transducer elements varying progressively over the area of said member in accordance with a predetermined law.

4. A compressional wave signaling device having a transmitting and/or receiving member with a continuous finite transmitting and/or receiving surface adapted to contact the signaling medium, said surface having dimensions greater than the wave length of the compressional waves of the signaling frequency as measured in the signaling medium, and means for vibrating and/or producing electrical response to vibration of said surface including a plurality of electroacoustic transducer elements mounted on and distributed over the opposite side of said member, the last-named side of said member being shaped to provide varying thicknesses etween central and edge portions, each of said transducer elements together with that portion of the mass of said member associated therewith forming a one-half wave length vibrating system at the signaling frequency.

5. A compressional wave signaling device having a transmitting and/orreceiving member with a continuous finite transmitting and/or receiving surface adapted to contact the signaling medium, said surface having dimensions greater than the wave length of the compressional waves of the signaling frequency as measured in the signaling medium, and means for vibrating and/or producing electrical response to vibration of said surface including a plurality of electroacoustic transducer elements mounted on and distributed over the opposite side of said member, each of said elements together with that portion of the mass of said member associated therewith forming a onehalf wave length vibrating system at the signaling frequency, the said transducer elements being distributed over the area of said member in a nonuniform manner so that some elements. will be associated with a greater portion of the mass of said member than other elements in accordance with a predetermined law.

6. A compressional wave signaling device having a transmitting and/or receiving member with a continuous finite transmitting and/or receiving surface adapted to contact the signaling medium, said surface having dimensions greater than the wave length of the compressional waves of the signaling frequency as measured in the signaling medium, and means for vibrating and/or producing electrical response to vibration of said surface including a plurality of electroacoustic transducer elements mounted on and distributed over the opposite side of said member, each of said elements together with that portion of the mass of said member associated therewith forming a vibrating system resonant at the signaling frequency, the mass ratios of the several transducer elements varying progressively over the area of said member in accordance with a predetermined law.

7. A compressional wave signaling device having a transmitting and/or receiving member with a. continuous, finite transmitting and/or receiving surface adapted. to; contact. the Signaling medium, said surface having dimensions greater: than the. wave len thyof the compressional Waves of the signaling frequency as measured in: the signaling medium, andmeansforvibrating and/or producing. electrical response to vibration ofv said surface including a plurality of electroacoustictransducer elements mounted on and.distributed over the :opposite side of; saidmember, each of; saidelements together with thatportion. of the mass. of, said member associated: therewith: forming a vibrating system resonant at the signaling frequency, the ratio of the mass of the. severaltransducer elements to that portionof themass of said member. respectivelyassociated therewith varying progressively over the. area of said member in accordance. with a predetermined law.

8; A compressional wave. signaling device. having atransmitting and/ or receiving member with a. continuousfinite transmitting and/or receiving surface, adapted to contact the signaling medium, saidsurface having dimensions greater than the wave. length of the compressional waves of the. signaling frequency as measured in the signaling medium, and means for vibrating and/or producing electrical response to vibration of said surface including a plurality of magnetostrictive tubes adapted to vibrate. and/or to be vibrated by said member mounted on and distributed over the. opposite side of said member, each of said tubes together with that; portion: of the mass of said memberassociated therewith forming a vibrate ing. system. resonant, at the signaling frequency; eacheofpsaid tubes. being associated with substantially the. same; pro-portion of the mass of said member but the masses of the several tubes'varying progressively over the area of the. said member: and. means for vibrating. and/or producing electrical response to. vibration of said tubes.

9. A compressionalxwave signaling device having. at transmitting and/or receiving member with a continuous finite transmitting and/ or receiving. surface adapted to contact the signaling medium, said surfacehaving dimensions greater than the. wavelength of the compressional waves of the signalingv frequency as measured in the signaling medium, and means for vibrating and/0r producing electrical response to vibration of said surface; including aplurality of magnetostrictive tubes adapted to vibrate and/or to' be vibrated by said member mounted on and distributed over the opposite side of said member, each of said tubes together'with that portion of the mass of said member associated therewith forming a onehalf wave length vibrating system at the signaling frequency, each of said tubes being associated with substantially the same proportion of the mass of said member but the masses of the several tubes varying progressively over the area of said member and means for vibrating and/or producing electrical response to vibration of said tubes.

EDWIN E. TURNER, JR. 

